Download it here http://www.orbithangar.com/advsearch.php?search=name&text=how+to+make
As you may notice it says how to make music for orbiter space flight simulator.
It is indeed a tutorial about MPT but since the hosting is about that space simulator, I had to add some bits at the end so people may add the resulting music to the sim.
If you are not familiar with Modplug Tracker, you may get familiar with it in no time if you follow that tutorial.
I flicked through it quickly and it seems like quite a nice introductory tutorial. Are you the author? Do you mind if I integrate it into the OpenMPT wiki (http://openmpt.xwiki.com/xwiki/bin/view/Main/WebHome) one of these days?